You might not care that it's been that way for a thousand years, but the point is that it's not "adding something" to beer. It's all just beer. It's been that way for as long as "beer" has existed in Europe. Nothing has been added that is not an acknowledged and accepted part of "beer."
Taking your argument you could say that beermakers are "adding something" when they include hops. While that might be technically true, it's not considered beer, without the hops. And adding TOO much hops results in crappy-tasting American IPAs, but not adding any hops would be just as bad.